The idea is that the brighter a pixel on the heightmap is, the higher the elevation of the resulting mesh is. So the first step is to get the values for all the pixels in the PNG. This is accomplished by drawing the image onto a canvas, and then getting the pixel data from it. It looks something like this:

Please keep in mind that in this case the width in pixels is 1 more than the number of segments in the plane. (If there’s one segment, theres 2 vertices, two segments, 3 vertices, and so forth..) If that’s not the case more work is required, because the landscape will be “skewed” if height and width dont correspond correctly.

It was fun to do and I learned a bunch of stuff about Mac OS X. It was probably also the last side-project ever written in Objective-C for me, since the Apple world is switching to Swift now. (Which is good.)

Sadly, I cannot distribute the app through the AppStore, because it cannot be sandboxed using the APIs it does (Accessibility). Which means I will probably never earn enough money to buy a happy meal with it.

I had a UIPageViewController in scrolling-mode that would allow to pan between view-controllers using a finger gesture. However, I wanted to restrict the panning area to a certain area of the screen, for example as shown in this screenshot:

I do it by subclassing the UIPageViewController, finding its UIScrollView, and adding a new UIPanGestureRecognizer to that scrollView.

I set my subclassed UIPageViewController to be the delegate of that new UIPanGestureRegognizer. I then implement two delegate methods:

In the last override I decide if I want to “eat the event” (reply YES) or if I want the original UIPanGestureViewRecognizer of the UIScrollView to handle it (reply NO). So, the YES-reply means the UIPageViewController will not scroll to the next ViewController.